Chemotherapy and radiation treatment are the biggest reason for hair loss. However, hair thinning may be a sign of Hodgkin’s lymphoma, which is a rare type of cancer. It grows in the lymphatic system, and the common signs of this dangerous disease include fever, fatigue, weight loss, night sweats, and painless inflammation in the neck, groin, and under the arms. However, along with these symptoms, you can also experience hair loss. If you are experiencing rapid hair thinning and you’re concerned about these signs, you should seek medical treatment.